24 Hour Summary

The maximum pollutant concentrations measured during the last 24 hours across Wales are shown below. Summary graphs showing the last seven days are available for each pollutant in the left hand column of the table.

Site 8 Hour mean
Ozone
µgm-3
Hourly mean
Nitrogen dioxide
µgm-3
Max 15 min mean
Sulphur dioxide
µgm-3
Running 24 Hour mean
PM2.5
Particles
µgm-3
Running 24 Hour mean
PM10
Particles
µgm-3
Aston Hill
87
Low (3)
10
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured 25
Low (1)
Not measured Not measured 15
Low (1)
Caerphilly Blackwood High Street
Not measured 48
Low (1)
Not measured Not measured 18
Low (2)
Caerphilly Fochriw
Not measured Not measured Not measured 13
Low (2)
No Data
Caerphilly Islwyn Road Wattsville
Not measured 37
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 56
Low (1)
Not measured Not measured 19
Low (2)
Cardiff Castle Street
Not measured 62
Low (1)
Not measured 13
Low (2)
21
Low (2)
Cardiff Centre
86
Low (3)
22
Low (1)
2
Low (1)
14
Low (2)
17
Low (2)
Cardiff Newport Road
Not measured 53
Low (1)
Not measured Not measured 23
Low (2)
Chepstow A48
Not measured 49
Low (1)
Not measured 15
Low (2)
24
Low (2)
Cimla Road / Victoria Gardens
Not measured 38
Low (1)
Not measured Not measured Not measured
Cwmbran Crownbridge
92
Low (3)
29
Low (1)
Not measured Not measured 19
Low (2)
Hafod-yr-ynys Hill Roadside
Not measured 44
Low (1)
Not measured Not measured Not measured
Marchlyn Mawr
No Data 3
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 43
Low (1)
Not measured Not measured Not measured
Narberth
77
Low (3)
3
Low (1)
1
Low (1)
7
Low (1)
10
Low (1)
Newport M4 Junction 25
55
Low (2)
109
Low (2)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 25
Low (1)
Not measured 17
Low (2)
22
Low (2)
Port Talbot Dyffryn School
Not measured Not measured Not measured 13
Low (2)
22
Low (2)
Port Talbot Little Warren
Not measured Not measured Not measured 14
Low (2)
16
Low (1)
Port Talbot Margam
77
Low (3)
42
Low (1)
69
Low (1)
15
Low (2)
41
Low (3)
Port Talbot Prince Street 2
Not measured Not measured Not measured 11
Low (1)
34
Low (3)
Port Talbot Twll-yn-y-Wal Park
Not measured Not measured Not measured Not measured No Data
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured 15
Low (2)
34
Low (3)
Rhondda Mountain Ash
Not measured 74
Low (2)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 89
Low (2)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 51
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
No Data 32
Low (1)
Not measured Not measured Not measured
Swansea Hafod DOAS
68
Low (3)
84
Low (2)
Not measured Not measured Not measured
Swansea Morfa Road NOX
Not measured No Data Not measured Not measured Not measured
Swansea Morriston Roadside
No Data No Data Not measured No Data Not measured
Swansea Port Tennant Roadside
Not measured 28
Low (1)
Not measured 17
Low (2)
Not measured
Swansea Roadside
Not measured 37
Low (1)
Not measured 13
Low (2)
18
Low (2)
Swansea St Thomas DOAS
95
Low (3)
30
Low (1)
17
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured 64
Low (1)
Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured No Data No Data
Wrexham
Not measured 32
Low (1)
3
Low (1)
13
Low (2)
19
Low (2)
Wrexham Chirk
Not measured 26
Low (1)
Not measured 4
Low (1)
13
Low (1)
Wrexham Chirk Community Hospital
Not measured 18
Low (1)
Not measured 5
Low (1)
14
Low (1)